Rodrigo Barros Rocha

Componentes primários e secundários do rendimento de óleo de pinhão-manso

The definition of the most suitable plant selection criteria is especially important for Jatropha curcas L. as subsidies the genetic progress estimates and the ideotype characterization, described in terms of the traits that are thought to enhance genetic yield potential. The objective of this study was to estimate the direct and indirect effects of seven vegetative traits and four seed quality traits on J. curcas oil yield. The traits grain yield and the weight of the nuts showed direct and positive effect on the oil yield. The tree volume showed the major indirect and positive effect on the main variable through grain yield. The development of J. curcas with higher oil yield in the evaluated population has to consider the selection of plants with higher yield and tree volume, maintaining the variability of the grain quality traits.

Estimates of genetic parameters for physic nut traits based in the germplasm two years evaluation

In spite of increasingly widespread interest in planting physic nut, breeding efforts are still in its infancy. In that context, an important resource recently established aiming future breeding efforts was the assembly of a germplasm bank with near 200 accessions. The objective of this study was to estimate genetic parameters, repeatibility coefficients and genetic correlation between seven traits, measured in 110 accessions (half sib families) of this germplasm bank in different stages of development. The results show that higher relative values of additive variance were only found for yield and height, and the existence of low environmental variation (either of temporary or permanent nature) among plots within blocks. Given the high repeatibility values found for all traits, on average three measurements are necessary to predict, accurately and efficiently, the true breeding value of an individual. Based on the results of genetic correlations, breeding effort should initially be use track trees with increased stem diameter, elevated number of branches and canopy volume so as to increase the chances of finding an exceptionally highly productive tree.

Evaluation of the Efficacy of Acaricides Used to Control the Cattle Tick, Rhipicephalus microplus, in Dairy Herds Raised in the Brazilian Southwestern Amazon.

The adult immersion test (AIT) was used to evaluate the efficacy of acaricide molecules used for control of Rhipicephalus microplus on 106 populations collected in five municipalities in the state of Rondônia in the Brazilian South Occidental Amazon region. The analysis of the data showed that the acaricide formulations had different efficacies on the tick populations surveyed. The synthetic pyrethroids (SPs) acaricides were the least effective (48.35–76.84%), followed by SP + organophosphate (OP) associations (68.91–81.47%) and amidine (51.35–100%). For the macrocyclic lactones (MLs), the milbemycin (94.84–100%) was the most effective, followed by spinosad (93.21–100%) and the avermectins (81.34–100%). The phenylpyrazole (PZ) group had similar efficacy (99.90%) to the MLs. Therefore, SP acaricides, including associations with OP, and formulations based on amidine presented low in vitro efficacy to control the R. microplus populations surveyed.

Diversidade de fungos micorrízicos Epulorhiza spp. isolados de Epidendrum secundum (Orchidaceae)

SUMMARY : DIVERSITY OF MYCORRHIZAL FUNGI Epulorhiza spp.ISOLATED FROM Epidendrum secundum (ORCHIDACEAE) Rhizoctonia -like mycorrhizal fungi Epulorhiza spp. have been isolated from orchids ofthe genus Epidendrum and have been used to promote the symbiotic germination of orchidseeds. Epidendrum secundum is a widely distributed orchid in campo de altitude (highelevation grassy vegetation) regions of the State Park of Serra do Brigadeiro (PESB), MinasGerais, Brazil, and little is known about the mycorrhizal relationships of this species in thepark. The objective of this study was to evaluate the morphological diversity of Rhizoctonia- like mycorrhizal fungi isolated from four E. secundum populations growing in three regionsof a campo de altitude , in the region of Totem Deitado Mountain, PESB. Twenty-six fungalisolates were obtained, all belonging to Epulorhiza . The quantitative and qualitativemorphological characteristics revealed, in general, low variability among the fungi isolatedfrom the same orchid population and among isolates from the same region, but high variabilityamong the fungi isolated from the populations from different regions. Based on thesemorphological characteristics, the isolates were separated into four groups. The first consistedof the fungi from populations I and II from region A, the second of isolates from population IIIfrom region B, the third of isolate M61 from population II from region C, and the fourth of asingle isolate obtained from population IV from region C. The morphological variabilityobserved indicates the existence of diversity of

Eficiência da seleção para incremento do teor de óleo do pinhão-manso

The objective of this work was to estimate the genetic parameters of physic nut (Jatropha curcas) grain quality traits and to quantify the genetic progress with selection. Seed oil content, and seed, kernel, and shell weights of 120 plants, randomly selected in a commercial planting, were evaluated at 36 and 48 months. Genetic progress was quantified by the evaluation of direct gains and by the use of selection indexes. The genotype x measurement interaction was significant for all evaluated traits; therefore, there are genotypes with different behavior in the two cropping seasons. The genetic parameters indicated a higher proportion of genotypic variation in the expression of the evaluated traits, and a trend of the genotypes to maintain their genetic superiority over time was observed. The genotype-ideotype selection index resulted in higher genetic gains and promoted a more balanced alteration in the trait means. The direct selection for kernel weight results in genetic gains similar to those obtained with the use of the selection indexes.

Estimate of genetic parameters and predicted gains with early selection of physic nut families.

An initial evaluation of early selection of physic nut genotypes based on phenotypic data is presented. In order to predict the genetic gains with early selection, genetic parameters, e.g. additive genetic variance, were first obtained for grain yield along with other numerous traits. The results demonstrated that additive genetic variance exists not only for grain yield, which is considered to be the most important trait for oil and biodiesel production, but also for numerous other traits. The predicted genetic gains for grain yield, considering the selection of the 30, 20, 10 and 5 best families in the second crop year are respectively, 40.47, 48.43, 61.78 and 70.28%. With the selection of highly yielding physic nut genotypes indirectly genotypes with enhanced volume would be also selected, because yield exhibits moderate to high genetic correlations with height e canopy volume. The results here presented demonstrate the potential of the population gathered in the Brazilian physic nut germplasm bank for genetic breeding purposes and that superior physic nut families can be selected with high accuracy based on the evaluation of its second crop.

Seleção de genitores de Eucalyptus grandis e de Eucalyptus urophylla para produção de híbridos interespecíficos utilizando REML/BLUP e informação de divergência genética

RESUMO – Foram avaliadas 363 progenies de meios-irmaos de Eucalyptus urophylla e de 245 progenies de meios-irmaos de E. grandis, visando a selecao de genitores para a producao de hibridos interespecificos em cruzamentos controlados em dialelo circulante, com base em seus valores geneticos preditos. Os ensaios foram conduzidos em Guanhaes, MG, no delineamento de blocos casualizados com cinco repeticoes, parcelas lineares de seis plantas para E. urophylla e oito plantas para E. grandis, no espacamento de 3,0 x 2,0 m. Os parâmetros geneticos foram estimados adotando-se modelos mistos com uso do procedimento REML/BLUP (maxima verossimilhanca restrita/melhor predicao linear nao viesada) para diâmetro a altura do peito (DAP), altura total (ALT) e volume individual (VOL). A predicao dos valores geneticos foi feita somente para (DAP), caracteristica que foi utilizada para selecao. Em E. urophylla, foram obtidas as estimativas de herdabilidade no sentido restrito de 0,2785 e de acuracia da ordem de 61%, e em E. grandis, herdabilidade de 0,2247 e acuracia de 53%. A selecao dos 100 genitores de cada especie individualmente proporcionara ganhos geneticos na ordem de 20,6% em E. urophylla e de 16,4% em E. grandis. Ganho genetico para DAP em torno de 35,0% podera ser obtido com o cruzamento dos 10 individuos selecionados para cada especie, portadores das maiores estimativas de divergencia genetica.

Desempenho agronômico e ganho genético pela seleção de pinhão‑manso em três regiões do Brasil

The objective of this study was to evaluate the agronomic performance and genetic gain by the selection of half-sib families of physic nut grown in three Brazilian regions. Based on previous phenotypic selection, three progeny tests were performed, in 2008, in the municipalities of Planaltina, DF, Nova Porteirinha, MG, and Pelotas, RS. A randomized complete block design was used, with three replicates, and five plants per plot. Randomly collected seeds from a population without selection were used as control. There was a significant interaction between the effects of genotypes and environments. Estimates of variance components and genetic parameters indicated that it is possible to obtain genetic gains from selection of the best families in the evaluated environments. In each environment, at least one family was selected with a higher performance than the control treatment. Mass selection in the three environments provided 72% of genetic gains. The agronomic performance had a high correlation coefficient between the environments of Planaltina and Nova Porteirinha, which did not occur in Pelotas. Genotype x environment interaction should be considered in the recommendations of physic nut genetic material for different environments.

The Importance of Jatropha for Brazil

Fossil derived fuels currently supply most of the world’s energy, even though it represents a finite resource. Aiming at reducing the fossil fuels dependency, alternative sources of energy have been pursued in the last few years. In view of the urgent need to develop new technologies that may enable the widespread use of environment friendly forms of energy, biofuels in general and biodiesel in particular, are receiving considerable attention throughout the world and especially in Brazil. Due to the high quality of its oil that meets the rapeseed quality standard, to the fact that its oil can be easily converted into biodiesel, and its wide adaptability, physic nut (Jatropha curcas) has been considered a potential crop to serve as feedstock for biodiesel production. In that context, this chapter demonstrates the potential of physic nut as a biofuel crop, highlighting however the existing challenges to its wide adoption as a fuel crop. Even facing enormous challenges (detailed below), our cautiously yet optimistic vision is that a dense and directed research program may successfully make physic nut a viable feedstock for biodiesel production. In that respect we detail the Embrapa research initiative drawn to address many of the existing challenges.

Yield performance of half-sib families of physic nut (Jatropha curcas L.)

Among the oilseed plants, physic nut stands out for its yield potential and for the quality of its oil for biodiesel and biokerosene production. Currently, low seed yield, uneven fruit maturation and the lack of high yielding genotypes limit the viability of this crop. Here we evaluated the yield performance of a population, structured in 16 half-sib families, in the 2nd, 3rd and 4th years after planting (2009-11). Seed yield showed variability. The families maintained their relative performance over time. Contrary to expectations, seed yield was lower in the 4th year, probably due the increased competition between plants and leafhopper (Empoasca spp) incidence. Temporal yield stability and adaptability estimates indicated a trend toward maintaining plant superiority over time, and families 7 (1059 kg ha-1) and 12 (984 kg ha-1) showed the best stability and yield performance. Physic nut has the potential for greater yield gains.